The variation of the velocity of elastic waves and of ultrasonic transit times with the direction of propagation under the influence of an externally applied dc electric field was calculated on the basis of known elastic constants and recently determined effective electroelastic moduli for alpha quartz. Results are presented in graphical form for propagation directions in the three planes defined by the conventional Cartesian crystal axes. For each propagation direction the three possible acoustic modes are considered in conjunction with three mutually perpendicular field configurations.